1. Field of the Invention
The invention relates to real-time video transmission systems for transfer of video data via a communication system, network nodes of the communication system, and a method for transferring real time video data via a communication system, and preferably to a synchronous communication system formed as a ring network of two or more ports coupled in a daisy chain configuration to each another to allow communication.
2. Description of the Prior Art
A generally known communication system permits communication between nodes interconnected by a transmission line. Each node can transmit information and receive information via the transmission line. The communication system of interconnected nodes can be configured to have various topologies, such as a bus, ring, star, or tree topology, or a combination thereof.
A bus topology network is generally regarded as being linear. Transmissions from one node propagate along the transmission line and are received by all other nodes connected to the bus. A ring topology network, however, generally consists of a series of nodes connected to each another by unidirectional transmission links to form a single closed loop. Examples of a ring network are described in IEEE 802.5 and the Fiber Distributed Data Interface (FDDI) standards.
A chosen transmission line between nodes can be either wired or wireless, for example via copper wire, fiber optics, or via a wireless transmission medium.
U.S. Pat. No. 7,054,916 discloses a system for video transmission. Signals from video cameras are processed and assembled to individual information packets which include image information, control information, and header information indicating transmitter and receiver addresses. These information packets are transferred via the network and received by an addressed network node. An addressed network node decompresses and displays the video signals. Owing to the packet oriented transmission, variable latencies occur throughout the network. This is not critical for applications like webcams. In other applications in which video signals of good quality must be transferred with low latency via a network, this is not acceptable.